Sulfur Dioxide → HCID 18357855, compound

Temperature

0 °C

To a solution of the product from Step D (1.73 g, 7.42 mmol) in THF (15 mL) cooled to -60° C. was added via syringe n-butyllithium in hexane (2.5 M, 3.56 mL, 8.91 mmol) over 5 min. After the addition was completed, the mixture was warmed to 0° C. and stirred for 20 min. The mixture was re-cooled to -60° C. and a stream of sulfur dioxide was passed through the surface of the mixture for 20 min. The mixture was warmed to ambient temperature and the volatiles were evaporated. To the residue was added sodium acetate trihydrate (3.03 g, 22.3 mmol) and water (50 mL) and the mixture was cooled to 0° C. Hydroxylamine-O-sulfonic acid (1.51 g, 13.4 mmol) was added and the mixture was allowed to stir for 30 min. The reaction mixture was extracted with ethyl acetate (3×100 mL), dried over molecular sieves and concentrated to give an orange oil (2.25 g) which solidified on standing. The solid was crystallized from methanol-methylene chloride to give a colorless solid (1.21 g, 52%, first crop): mp 161°-162° C.

1. additionAfter the addition
2. temperatureThe mixture was re-cooled to -60° C.
3. temperatureThe mixture was warmed to ambient temperature
4. customthe volatiles were evaporated
5. temperaturethe mixture was cooled to 0° C
6. stirringto stir for 30 min
7. extractionThe reaction mixture was extracted with ethyl acetate (3×100 mL)
8. customdried over molecular sieves
9. concentrationconcentrated

ORD record

ord-7a6bfeabeae3493e90116fefd99d319d

Source dataset

uspto-grants-1993_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05240923